Chan O Y, Edwards M, Brown B
Department of Optometry and Radiography, Hong Kong Polytechnic University, Hung Hom, Hong Kong.
Ophthalmic Physiol Opt. 1996 May;16(3):203-10.
A new graphical calibration method was developed to convert the photorefractive reflex into refractive error. With this graphical method, the refractive error can be obtained for pupil sizes and for photorefractive reflex sizes which have not been precalibrated. In the conventional method, the refractive error associated with non-precalibrated pupil and reflex sizes is obtained by interpolating between neighbouring precalibrated points. This introduces error because the relationship between refractive error and pupil and reflex size is not linear. Three hundred and sixty-one children aged between 36 and 65 months were clinically examined and photorefracted. The refractive error obtained using retinoscopy and the eccentric photorefractor agreed well with each other, although the photorefractor tended to under-estimate refractive error. Using the referral criteria developed by Chan, O.Y.C. and Edwards, L.M. (Refraction referral criteria for Hong Kong Chinese Children. Ophthal. Physiol. Opt. 14, 259-256, 1994), the photorefractor had a sensitivity of 74.6% and a specificity of 96.4%. All the under-referred cases were borderline, having just failed the referral criteria. All the cases with hyperopia of > + 2.0 D, astigmatism of > 1.25 D and visual acuity of worse than 6/18 were identified.
一种新的图形校准方法被开发出来，用于将光折射反射转换为屈光不正。通过这种图形方法，可以获得未预先校准的瞳孔大小和光折射反射大小对应的屈光不正。在传统方法中，与未预先校准的瞳孔和反射大小相关的屈光不正，是通过在相邻的预先校准点之间进行插值来获得的。这会引入误差，因为屈光不正与瞳孔和反射大小之间的关系不是线性的。对361名年龄在36至65个月之间的儿童进行了临床检查和验光。尽管验光仪往往会低估屈光不正，但使用检影法和偏心验光仪获得的屈光不正结果彼此吻合良好。根据Chan、O.Y.C.和Edwards、L.M.制定的转诊标准（《香港华裔儿童的屈光转诊标准》。《眼科生理光学》14卷，259 - 256页，1994年），验光仪的敏感度为74.6%，特异度为96.4%。所有转诊不足的病例都处于临界状态，刚好未达到转诊标准。所有远视度数> + 2.0 D、散光度数> 1.25 D且视力低于6/18的病例都被识别出来了。
